Reserve switch for diving equipment

ABSTRACT

The invention relates to a valve assembly for diving equipment having an air inlet to which a container bottle containing pressurized air may be attached and an air outlet to which the breathing equipment is attachable. Between the air inlet and air outlet is reserve valve means which is biased in an opening direction by pressurized air on the downstream said thereof and in a closing direction by valve actuator means which operates to close the reducing valve when the air pressure on the downstream side drops to a predetermined minimum pressure. First and second guide means are provided for the valve actuator means which actuator means has a range of movement relative to each of said guide means with said movement being automatic relative to the first guide means and manually controllable relative to the second guide means, The valve actuator means is transferable from the first guide means to the second guide means only at a point corresponding substantially to said minimum pressure.

United States Patent 1 Lerris 1 May 8, 1973 541 RESERVE SWITCH FOR DIVING 3,244,196 4/1966 Replogle ..l37/63 R EQUIPMENT 3,477,463 11/1969 Worden ..l37/6l2.l X 3,552,434 l/197l Haenky ..25l/286 [75] Inventor: Hans Otto Lerrls, Nordborg,

Denmark Primary ExaminerSamuel Scott [73] Assignee: Danfoss A/S, Nordborg, Denmark At rneyWayne B. Easton [22] Filed: Apr. 7, 1971 [57] ABSTRACT [21] Appl' 1322114 The invention relates to a valve assembly for diving equipment having an air inlet to which a container [30] Foreign Application Priority Data bottle containing ressurized air ma be attached and P y an air outlet to which the breathing equipment is at- 1970 Germany 18 1479 tachable. Between the air inlet and air outlet is reserve [52] U s C 137/612 1 137/63 R valve means which is biased in an opening direction by [51] 17/04 pressurized air on the downstream said thereof and in [58] Fieid oi'.;;;;c'i;"'........."'1'I'I11'i5}3'i 1 614 19 a cksing directim by means which {37/63 RT'1/255 operates to close the reducing valve when the air pressure on the downstream side drops to a predetermined [56] References Cited minimum pressure. First and second guide means are provided for the valve actuator means which actuator UNITED STATES PATENTS means has a range of movement relative to each of 3 561 477 2H9. Pinto 137/614 19 said guide means with said movement being automatic 2933283 4/1960 251/254 X relative to the first guide means and manually control- 3:127:786 4/1964 1 5,: ":251/253 X lable relative to the second guide means, The valve ac- 2 217 9 3 10 940 Mueller 151 2 X tuator means is transferable from the first guide means 1,702,021 2/1929 Rodler ..251/255 to the second guide means only at a point correspond- 2.945,703 7/1960 Ballard ..25l/253 X ing substantially to said minimum pressure. 3,037,502 6/1962 Gibbens et a1. ..137/63 R 3,207,179 9/1965 Klaques ..l37/6l2.l 7 Claims, 6 Drawing Figures l M v1 /37 Patented May 8, 1973 3,731,704

2 Sheets-Sheet i I F I F? Q I4 I Z L J J Q 5/ RESERVE SWITCH FOR DIVING EQUIPMENT The invention relates to a reserve switch for diving equipment, which switch closes when the pressure in a pressurized-gas container falls below a predetermined level and which then has to be opened again by means of a manually actuated device for drawing off further gas.

For the purpose of supplying oxygen to a diver, use is made of pressure containers (known as bottles) which are filled with oxygen or air under high pressure, e.g. 200 atmos. This pressure drops as the gas is consumed. Mounted on the pressure container is a cut-off valve which closes the bottle when it is not in use. Following this, is a reserve switch. This is actuated when the pressure in the bottle falls below a certain minimum level, e.g. 30 atmos., and a closure member in the switch prevents the discharge of gas. This is the signal for the diver to begin to surface. By actuating the switch he can cause further gas to be discharged, and he does this for example by opening a by-pass which short-circuits the said closure member, and he can thus use up the remaining contents of the bottle. Adjacent the bottle is the actual breathing apparatus. This usually consists of a reduction stage which reduces the pressure in the bottle to 4 atmos., above the pressure of the water for example, and optionally of a dispensing stage which by further reduction discharges air at a pressure corresponding to the depth of the water.

If the diver has inadvertently actuated the reserve switch without noticing, then the interruption of the discharge of gas which acts as a signal for surfacing does not take place, since the gas can flow unrestrictedly through the opened reserve switch. Lack of gas occurs only when the contents of the bottle are used up, but then it is no longer possible for the diver to surface slowly.

The object of the invention is to provide a reserve switch which ensures that the interruption of the discharge of gas acting as a signal occurs in a very reliable manner and that thereafter an adequate reserve is still present in the bottle.

According to the invention, this object is achieved by providing the reserve switch with a locking device which is responsive to the entry pressure and which permits the switch to be permanently displaced from its working position only when the pressure falls below a predetermined release pressure.

The reserve switch cannot therefore be permanently brought into the reserve position at all so long as the bottle pressure and thus the entry pressure are at so high a level that actuation of the reserve switch is not necessary. Conversely, the reserve switch can only be actuated when the entry pressure has dropped so low that actuation of the reserve switch is required. lnadvertent actuation of the reserve switch is thus precluded.

A particularly simple construction is obtained if the locking device secures the manual actuating device against displacement above the release pressure. If the manual actuating device is immobilized dependent upon pressure, it cannot be displaced at an inopportune moment. A further possibility consists in, for example, fitting the manual actuating device with a return spring which continues to act until the pressure has fallen below the release pressure.

The release pressure is preferably at most somewhat greater than the predetermined minimum pressure at which the reserve switch closes. The two pressures may also be the same. This ensures that actuation of the switch can take place only when it is necessary to switch over to the reserve.

Furthermore, a pressure-responsive actuating device can both close the reserve switch and release the locking device. The pressure-responsive actuation of the locking device therefore involves only a slight additional complication in, and cost of, the construction.

Additionally, the pressure-responsive actuating device can control a reducing valve fitted ahead of it. In this way, the cost of the construction is still further reduced since at least one reducing valve is in any case necessary. Irrespective of the pressure in the bottle, the reducing valve keeps the pressure at the reserve switch substantially constant until the pressure in the bottle has fallen below the level for which the reducing valve is rated. The reserve switch is therefore subjected to lower pressures; however, when it is required to respond, its entry pressure is substantially equal to the pressure in the bottle.

In a further form of the invention, the actuating device can incorporate an actuating element which is actuated by a diaphragm, which is acted upon one side by the entry pressure and on the other by the water pressure, and by a biasing spring. This diaphragm also acts as a sealing element. Because of the effect of the pressure of the water, the release pressure and the pressure at which the reserve switch responds change in dependence upon the diving depth. The greater the diving depth, the greater also is the reserve available in the bottle at the release pressure.

It is advisable for the locking device to be constructed with a fixed stop and a movable stop which, under the effect of the entry pressure, is displaceable parallel to the stop surface, is released from the fixed stop when the release pressure is reached and, in this position, permits a movement past the fixed stop, which movement is linked with the actuation of the reserve switch.

In this arrangement, the movable stop on the locking device can be provided on an axially displaceable rotary knob which is connected to the closure member of the reserve switch, which takes the form of a valve, the knob upon rotation, opening the valve as a result of a guided movement on an inclined surface. The pressureresponsive closure member of the reserve valve also acts as a switch member which can be brought into a permanently open or reserve position as a result of the guided movement on the inclined surface.

Particular advantages accrue if the reserve switch is provided with a return spring which moves it from its reserve position into its working position, and if immobilization automatically ceases in the reserve position when the entry pressure rises above a predetermined locking pressures. With this arrangement, the reserve switch can be readily checked to see that it is functioning correctly. If the bottle is blocked and the air in the valve arrangement is discharged, the pressure in the valve arrangement rapidly drops below the release pressure, so that the reserve switch can be brought into the reserve position where it is immobilized. If the cutoff valve on the bottle is opened again, the pressure in the valve arrangement rises again. As soon as' the locking pressure has been exceeded, the reserve switch springs back into its working position under the action of the return spring. This movement can be observed from the corresponding movement oftt-he manual actuating member.

This construction can be achieved by an arrangement in which the return spring biases the rotary knob in the direction in which it returns to its working position, and a latching notch is provided at the end of the ramped surface, a part of the rotary knob moving out of the notch when the predetermined locking pressure is exceeded.

The invention will now be described in more detail by reference to an embodiment illustrated in the drawing, in which:

FIG. 1 is a schematic illustration of a control system in which the reserve switch of the invention is used,

FIG. 2 shows a section through a form of valve arrangement in which a reserve valve in accordance with the invention, can be fitted, the directions in which the passages extend being shown schematically,

FIG. 3 is a longitudinal section through a manual actuating device with a locking means,

FIG. 4 shows part of FIG. 3 in another working position,

FIG. 5 shows part of FIG. 3 in yet another working position, and

FIG. 6 illustrates schematically the stops of the locking device.

FIG. 1 shows a unit 1 which, together with a union 2 can be mounted on a pressure bottle 3, and to the out let port 4 of which can be connected diving equipment, e.g. breathing apparatus 5, while the bottle 3 can be filled with pressurized gas by way of the charging part 6 of the unit 1. The unit 1 contains a cutoff valve 7, a reducing valve 8, a reserve switch 9, which takes the form of a valve, and a non-return valve 10. The breathing apparatus comprises a reducing stage 11.

As far as possible, corresponding parts of the embodiment of FIG. 2, described below, are designated by the same reference numerals as used in FIG. 1.

The cut-off valve 7 is fitted with a knob 12 which presses a closure member 14 against a valve seat 15 when the screwed spindle 13 is tightened. The screwed spindle extends through the usual gland 16.

The reducing valve 8 contains a high-pressure chamber 17 and a low-pressure chamber 18. In the high-pressure chamber there is fitted a throttle element 19 which cooperates with the seat 20. The throttle element is biased by a spring 21 which is backed by a screw 22. A diaphragm 23 is clamped by its outer edge by means of an attachment 24. At its center the diaphragm carries an actuating member 25 which acts on the throttle member 19 through a needle-like extension 26. The low pressure in the chamber 18, the force from a spring 27 and the pressure in a chamber 28, which is connected to the surrounding water through an opening 29, act on the diaphragm 23. r

The reserve switch 9 is constituted by a valve, the 1 closure member 30 of which is constituted byan O-ring which cooperates with a sealing face 31. The actuating member 25 is provided with a spindle 32, which carries at its free end a rotary knob 33 and a pin 34. By rotating the knob, the pin can be displaced on an inclined surface 35 of a cam element 36, so that the reserve valve 9 is opened in a positive manner. In the fully open position, the pin 34 engages in a groove 37 at theend of the inclined surface 35, so that the reserve valve is immobilized in the reserve position.

In the at-rest position and when the pressure in the bottle is sufficiently great, the throttle member 19 bears against the seat 20. If air is drawn off at the outlet port 4, the pressure in the chamber 18 drops, whereupon the spring 27, with the help of the pin 26, lifts the throttle member 19 from the seat. In this way, the reducing valve 8 is opened to an extent such that the pressure in the chamber 18 is held at a substantially constant reduced level. If the pressure in the bottle falls below this prescribed low pressure in the chamber 18, the throttle member 19 is brought to the position at which the widest opening is provided; at the same time, the reserve valve 9 is sealed by the closing member 30 bearing on the seat. The diver notices the deficiency of gas. By rotating the knob 33 he opens the reserve valve and immobilizes it in the reserve position. He then has a sufficient supply of gas to enable him to surface.

As shown more clearly in FIG. 3, a return spring 38 is provided near the rotary knob 33. One end 39 of this spring engages in a bore in the rotary knob 33 and its other end 40 in a bore in the attachment 24. The return spring 38 seeks to force the rotary knob 33 from the reserve position into its working position, as shown in FIGS. 4 and 5. If the rotary knob 33 is in its reserve position and when the pin 34 therefore engages in the locking groove 37, there must obtain in the chamber 18 a predetermined pressure, the locking pressure as it is called, which lifts the pin 34 from the groove 37 before return due to the spring force can take place. The rotary knob 33 then springs into the working position shown in FIGS. 4 and 5. Here, the spindle 40 and thus the closure member 30 are enabled to move freely in the axial direction. FIG. 4 shows a normal working position. FIG. 5 shows the end position at which the entry pressure in the chamber 18 has fallen to such an extent that the closure member 30 is applied to its seat 31. The reserve valve 9 must then be manually opened from this position by rotating the knob 33.

The attachment 24 is provided with a fixed stop 41 and the rotary knob 33 with a movable stop 42. The movable stop 42 is displaceable axially with the knob 33, i.e. it moves in response to pressure. In the normal operating position, the stops 41 and 42 occupy the (broken-line) position indicated by the letter a in FIG. 6. It is therefore not possible to rotate the knob 33. Inadvertent displacement is thus precluded. If however the entry pressure in the chamber 18 drops, the movable stop 42 is displaced from the position shown in FIG. 4 into the position seen in FIG. 5. In this latter position release therefore takes place, i.e. the knob 33 can be freely rotated, the stop 42 moving into the position designated by the letter b in FIG. 6. This means that the reserve valve can now only be opened by hand when this is actually required.

The reserve valve remains in the open position until the locking pressure is re-established in the chamber 18, i.e. until the bottle 3 is refilled. Under the effect ofa higher release pressure, in the chamber 18, the reserve valve then automatically returns to the working position of FIG. 4, in the manner described. To prevent the locking stops 41 and 42 from causing any trouble, these have inclined run-up faces 43 and 44. The movable stop 42 also has a resilient stem 45.

Additionally, the unit has a safety valve 46 comprising a valve seat 47, a diaphragm 48, an actuating element 49, a biasing spring 50 and a set-screw 51. If for any reason, the pressure in the chamber 18 is too great, gas can be discharged through an outlet 52.

The same principle can be used if the reserve valve 9 is separated from the reducing valve 8, when it is fitted directly behind the cut-off valve 7 or when it is ofa different construction. For example, a reserve switch may have a pressure-responsive closure member and, separately therefrom, a switch element with a pressure responsive locking device.

I clam:

1. A valve assembly for diving equipment comprising a casing having an air inlet to which a container containing pressurized air may be attached and an air outlet, passage means in said casing between said air inlet and air outlet, reserve valve means in said passage means biased in an opening direction by pressurized air in said passage means on the downstream side thereof from said valve means, valve actuator means biasing said reserve valve means when the air pressure on the downstream side of said valve means drops to a predetermined minimum pressure, said valve actuator means including a spindle and knob mounted for axial and rotational movement relative to the axis of said spindle, first guide means for confining movement of said spindle in an axial direction and second cam and follower guide means for guiding said spindle along a combination axially and rotationally extending path, said actuator means having ranges of axial and rotational movement respectively relative to said guide means with a range of axial movement being automatic relative to said first guide means and a range of combined and rotational movement being manually controllable relative to said second guide means, said valve actuator means being transferable from said first guide means to said second guide means only at a point corresponding substantially to said minimum pressure.

2 A valve assembly according to claim 1 including reducing valve means controlled by said valve actuator means,

3. A valve assembly according to claim 1 wherein said valve actuator means utilizes environmental water pressure and spring means to bias said reserve valve means in a closing direction,

4. A valve assembly according to claim 1 wherein said first guide means includes a fixed guide portion on said casing and a cooperable movable guide portion on said valve actuator means,

5. A valve assembly according to claim 4 wherein said valve actuator means is axially movable along one path when engaged with said first guide means and is axially movable along a different inclined path and rotatable when not engaged with said first guide means, a knob connected to said valve actuator means,

6. A valve assembly according to claim 5 including spring means biasing said valve actuator means to remain in engagement with said first guide means and towards engagement with said first guide means when said actuator means is in engagement with said second guide means,

. A valve assembly according to claim 6 includlng groove means at one end of said inclined path to provide a locking position for said knob. 

1. A valve assembly for diving equipment comprising a casing having an air inlet to which a container containing pressurized air may be attached and an air outlet, passage means in said casing between said air inlet and air outlet, reserve valve means in said passage means biased in an opening direction by pressurized air in said passage means on the downstream side thereof from said valve means, valve actuator means biasing said reserve valve means when the air pressure on the downstream side of said valve means drops to a predetermined minimum pressure, said valve actuator means including a spindle and knob mounted for axial and rotational movement relative to the axis of said spindle, first guide means for confining movement of said spindle in an axial direction and second cam and follower guide means for guiding said spindle along a combination axially and rotationally extending path, said actuator means having ranges of axial and rotational movement respectively relative to said guide means with a range of axial movement being automatic relative to said first guide means and a range of combined and rotational movement being manually controllable relative to said second guide means, said valve actuator means being transferable from said first guide means to said second guide means only at a point corresponding substantially to said minimum pressure.
 2. A valve assembly according to claim 1 including reducing valve means controlled by said valve actuator means,
 3. A valve assembly according to claim 1 wherein said valve actuator means utilizes environmental water pressure and spring means to bias said reserve valve means in a closing direction,
 4. A valve assembly according to claim 1 wherein said first guide means includes a fixed guide portion on said casing and a cooperable movable guide portion on said valve actuator means,
 5. A valve assembly according to claim 4 wherein said valve actuator means is axially movable along one path when engaged with said first guide means and is axially movable along a different inclined path and rotatable when not engaged with said first guide means, a knob connected to said valve actuator means,
 6. A valve assembly according to claim 5 including spring means biasing said valve actuator means to remain in engagement with said first guide means and towards engagement with said first guide means when said actuator means is in engagement with said second guide means,
 7. A valve assembly according to claim 6 including groove means at one end of said inclined path to provide a locking position for said knob. 